Regulating apparatus



Jan. 13, 1931. A. v. LlvlNGsToN REGULATING APPARATUS i Filed May 28,- 192e PPP F- q. mijn INVENToR BY WPI-.dj

ATTORNEY.'

.Patented Jan. 13, 19731 UNITI-:D sTATEsPATENT orl'flcal ALAN vAnLEY LIVINGSTON, or, NEW HAVEN, CONNECTICUT, AssIGNon To THE can HEATING a LIGHTING conrANY, A ConroEaTIoN or NEW JERSEY BEGULATING APPARATUS Application led lay-28, 1928; Serial No. 112,219.

- This invention relates to electrical systems of distribution and more particularly to car lighting systems in which the generator may be driven, lfor example, from a car axle.

One of the objects of this invention is to provide a system of the above-mentioned' character in which apparatus of simple con-v struction and of thoroughly dependable acT tion may be employed'for efficiently and dependabl safeguarding the ystem and translating evices associated ttllerewith against changes Vin the electrical conditions.' An-y other object is to provide a4 system of the above-mentioned character which will be of` thoroughly dependable action and' well tions or changes in the electrical conditions which it is adapted to rectify, and to achieve these objects in a thoroughl, practical way and with simple and depen able apparatus. Other objects will be in part obvious or in part pointed out hereinafter'. y

The invention accordingly consists in the features/pf construction, combinations of elements, and arrangements of parts as will be exemplified in the structure tobe hereinafter describedand the scope of the application of which will be indicated' in the following claims. v

In the accompanying drawing, ,in which 40 are sho several of the possible embodiments o my invention,

Figure 1 1s a diagrammatic representation of the circuit arrangements and of the apparatus illustrative of certain features of my invention as embodied in a car lighting system, and

Figure 2 isa like representation of a modified and preferred form of system and apparatus. A

t Similar reference characters refer to sim- `ilar parts throughout the several views of the drawing.

Referring now to the drawing and more particularly to Figure 1, there 1s shown at 10 a generator'adapted to be driven, in a car lighting system, rom a car axle, for example; the generator -10 may be of the shunt wound typeV and is provided with a shunt. field 11 supplied with exciting current through a variable resistance referably taking the form of a compressi le carbon pile 12.4 The generator 10: is connected to the I main line conductors 13 and 14 and may supply energy to a storage battery 15 andA to` lamps 16, an automatic switch generally indicated at 17 being provided` for connecting the generator to the battery and lamps when the voltage of the generator reaches a predetermined value and for disconnecting the generator therefrom whenv the voltage drops to a predetermined value.

priate form. Preferably also, there is interposed between the battery 15 andthe lamps 16 a regulator generally indicated at 18; this esV This automatic j v switch 17 may take any suitable or approregulator 18 mayalso take any suitable-0r appropriate form, and is adapted to maintain substantially constant the voltage across the lamps 16 throughout such changes in voltage across the battery 15 asare due to the change in the state of charge of the battery v or as are due to such conditions as depend upon whether the battery is being charged or not. y f

Operative upon the carbon pile 12 is a lever 19 pivoted as at 20 and atjsubstan 1 tially like distances from the pivot'point 20, there are connected to the lever 19 the cores 21 and 22 of two solenoid's; the lever 19 is provided with an arm 23 for engaging the movable end of the carbon pile 12, and the lever 19 with its associated solenoid cores is preferably so arranged as to form a substantially balanced mechanical system. In.

order, however, to maintain the carbon pile 12 under some degree of compressionwhen the generator 10 is at-.re'storvstarting up, the' mechanical system operative upon the carbon pile' 12 is preferabl' somewhat out of balance',

and such an out o balance condition may achieved by means of a weight-24; attached to the lever 19 and at such a ,position as to tend to compress the carbon pile 12.

Operative. upon theA cores 21 and 2.2 are appropriate windings arrangedto be re'- sponsive to those electricalchanges inthe system which areintended to be rectified, and by way vof illustration, the windings are shown 'as being responsive to` changes in the voltage.l lAbout the core 22 are two windin s 25 and 26, adapted to coact one with the ot er and about the core 21 is a win ing 27. At thispoint it might be noted that the solenoids are preferably so constructed and .designed .as to give a substantially constant pull at thenormal voltage and in all positions of the movable core throughout theoperating'range of thelatter. e

The windings 25 and 27 are preferably connectedl '.-in series with each other but through a variable resistance 28 and the filamentv 29 of a thermionic device 30, preferably ofthe two-element type, and having an appropriate anode or plate 31 coacting with the other' cathode 29. The circuitof the windings 25 and 27 will thus be seen to be as follows :-'From one side of the generator 10, as from thel main line conductor 14, then conductor 32, filament 29, adjustable resistance 28, winding 25, conductor 33, winding 27, conductor 34'and thence to the` other main line conductor 13 and hence to the other side of thegenerator-lO. Changes in voltage of the system,therefore, will affect in like degree theheating of the filament cathode 2 9 and also the energizatio of windings 25 and 27 of the two solenoids, the'latter acting, as will be clear, inopposition to each other. r

The ,circuit' of the winding 26, which coacts with the winding 25, uponthe core 22, is included in the plate circuit of the thermionic device 30 and will be seen tobe substantially as followsrz--From one terminal of winding 26, adjustable resist-ance 28, cathode 29,`

thencethrough the available electron path of the device 3() to the platev 31, conductor 35, secondary winding 36 of an appropriate transformer, and thence to the terminal of the coil' 26. A condenser 37, bridged across the coil 26 acts to smooth-out the half-waves of the current flowing in the plate circuit due to the appropriately high alternating potential supplied in the plate circuit by-the secondary winding 36 of the transformer.

The primary winding 37 of the transformer 36.-37 is connected by conductors 38 A and 39 to a'suitable source of alternating current. This source may take the form ofv a converter or motor-generator operated from the main line'conductors` of the system, .as

-will be made more clear hereinafter in connection with Figure, 2, or it may take the form of the armature of the generator 10 itself, it being understood that the armature windings of the generator 10 may be conparture -rent output of the generator substantially constant during the charging of the storage battery 15; las the latter approaches substantially full'charge, however, its back e. m. f. rises substantially rapidly so that, if the generator voltage is thereupon kept at an appropriate relatively constant value, the charging current to the battery will taper olf and the battery thus safeguarded against over-charge. It is at such an appropriate voltage that the regulating apparatus illustratively shown in Figure 1 is adapted to maintain substantial constancy against the speed changes of the generator 10, as well as to maintain such relatively constant voltage against whatever 'changing conditions in the system may tend to bring about a dcthereof. And, as illustratively shownin Figure 1, the apparatus will maintain the generator voltage substantially constant and preferably at a value such that, as the battery 15 approaches substantially full charge, the back voltage of the latter approaches or equals the voltage maintained v constant by the regulator so that the battery by upon thecore 22 substantially equal the ampere turns provided by the winding 27 and corresponding pull exerted thereby upon the core 21, respectively. When, therefore, the-voltageof the generator is at the desired value, the forces active upon the cores 2l and 22 are substantially equal to each other, due provisionl being made for compensating for the effect of the weight 24, and the lever 19 will be maintained in equilibrium and the pressure upon the carbon pile 12 held at a corresponding value. Likewise, at this intended voltage, the filament 29 will be heated to an appropriate and operative degree, and preferably at such a value that the thermionic device 3() may be made to operate throughout that portion of its operating characteristic which is below the saturation point or below the knee of the characteristic. The adjustable resistance 28 may be utilized to adjust the several parts in order to bring about the conditions above-mentioned.-

The winding 25 is preferably` proportioned with respect` to the winding 26 so that the former contributes about of the necessary ampere turns for operation upon'the core 22; this relation of the coils 25 and 26,

however, may be varied throughout a Wideextent, as may be desired and furthermore, if desired, the coil may be entirely omitted and the coil 26 adapted and designed to supply thegampere turns necessary for action upon the core 22.

y Assuming, however, that a changein the voltage of the system Atakes place, due, for example, to a changein the speed of thel generator 10, and assuming, furthermore, that the voltagec increases, the energization of' the solenoid 21-27 -will be correspondingly increased, but a part of the thus increased pull exerted by the winding 27 is counteracted by a like increase in the pull exerted by the winding 25 operative upon the core 22. At the. same time, however, the same voltage increase causes a corresponding increase in the heating of the cathode 29 of the thermionic device v30, s o that the con-y ductivity of the electron. path between the two electrodeswof the device 30 becomes in-4 creased but in :lispreportionatelyV reaterI degree; also the volta e incrmeise to increase the alternating otential supplied bythe slip rin and t usto increase in substantially 1i e degree the rpotential effec.

tive in the late circuit of the thermionic device 30. T ese changes in heatin of the {ilament 29 and in the potential o `the anode 31, each substantially directly `roportional to the change in the voltage, ring about, however, due to the characteristics of the 4thermionic devgigce() and due to thtplortions .of the charcteristicsofhnlatter r\ou hout which the device ,30 is operated, a is-\ proportionately greater increase in the enwJ ergization of the winding 26. The ampere turns thus effective on the core 22 are made *to relatively greatly preponderate overthe ampere' turns effective in the winding 27 upon Y the core 21, so that there is promptly exerted ing of the cathode 29, thefpotential of the d 'windings active upon the two cores, arethus,

a powerful `movement ofthe lever 29 in a clockwise direction about its pivot 20, thereupon to relieve the pressure on the pile 12, and by correspondingly increasing the re-` sistance in the circuit of'the field winding 11, to bring about a reduction to normal of the voltage of the generator 10.A The heatplate 31, andthe energization of the several 4may be and preferably is supplemented by a corresponding decrease in th otential of the plate 31, is made, by virtue/o the character istic of 'the thermionic device 30, to rapidly ective \advantage o havinlg Sure diminish the ener zation of the winding 2,6 operative upon e core 22 but to a much greater extent than is the corresponding decreasefin the energization of the winding 27 operative upon the core 21. The solenoid 214-27 is thus quickly made effective to become powerfully effective to increase the pressure upon the carbon pile 12, and thus to effect a Vcorresponding ra id increase land restoration to normal of t e voltagejof the generator 10.

It will thus be seen that, while, when normal electrical conditions are prevailing inthe system, thel two opposing solenoids are substantially equal in their opposing effects and maintain the mechanical system in a state of equilibrium, yet ther occurrence of a departure from the normal or desi/red electrical conditions is made to bring about a rapid and powerful preponderance of one of the opposin solenoids over the other. A

high degree o sensitivity is thus achieved, and this as well as many other advantages, is achieved, to ether with the very important the two solenoids electricallyrmagnetica y and mechanically of substantiall\'\identical construction. Furthermore, a sistances need not. beemploye since, irrespective ofl whatever temperature changes may be balanced out by reason of the windings 25and 27 being in the same circuit, dif

so temperature com ensating referenees in action of the two solenoidsdue to differences in tem erature become sub-v stantially immaterial ecause of the dis roportionately greater response of the t ermionic\de lce .30v to a given increment of change ginithelectrical conditions in the system. l' K Referring no w toFgnre 2, `it may first be noted that the coil -27 operativeupon the vloo core 21 is connectediby conductors 41 and 42 directly across the storage battery 15,

so as to'be' energized by the latter when thev generator 10 is at vrest or operating at'such'.. a speed that the4 main-switch 17 is open. p `The'solenoid 21-1-27 may thus act to maintain the carbon pile` 12 under substantial 1 and permitti egree of compression under: the conditions pointed out above, thereby avoiding the' use vof la device such as the weight `2410i Figure u they mechanical system of the regulator of" igure 2` to be substantially plrfectly balanced; thus the'picking up of t e while as soonas the mainswitch 17 is generator promptly is at all-tixnes=-in` closed, the coil 27 'iselectrically .positioned to .be responsive tolvoltage changesso thatv its action may be substantially similar to the coil 27 hereinbefore described in connection with Figure 1. v

In he arrangement of Figure 2, the; 'rill I mary windin of the transformer36-3 is,v

supplied wit an alternating potential-,of suitable value by means ofthe motor rgenerator or converter generally indicated at 43 and adapted to be supplied with energy from the main line conductors 13 and 14, to which it is connected by the conductors 44 and 45 respectively, though it will .be understood that the main generator 10 may be made, as illustratively shown and described in connection with Figure 1, to supply the appropriate alternating potential. The winding 25, which coacts with the winding 26, with respect to the core 22 at the opposing end of the lever 19, will be seen to be connected to be responsive to the changes in the electrical conditions of the system, illustratively set forth as voltage changes. The circuit of the winding 25 will be seen to lead from one side of the generator 10, as the main line conductor 14, thence through conductor 32, filament cathode 29 andtherniionic device 30, adjusting resistance 28, winding 25 and thence by way of conductor 46 to the main line conductor 13 and hence to the other side of the generator. A

The operation of the apparatus nd system of Figure 2 will be clear, itisl elieved, fromwhat has'been set forth in detail 'in connection with Figure 1. It may generally be noted, however, that a change in the voltage of the system from the desired -value at which thev two 'solenoids are substantially equally opposed in their effect and maintain the mechanical system operated thereby in substantial equilibrium, causes the rapid and 'relatively great preponderance of the one over the other due to the peculiar characteristics of the thermionic device 30, so that there is achieved not only highly sensitive response of the regulating apparatus but also a powerful action thereof to bring about rectification of the changes in the electrical conditions of the system. Differences Ain action or effect of various of the coils or windings of the regulating apparatus of Figure 2 need not be compensated for, as is lcommon practicefby the inclusion in the respective circuits of relatively high compensatingv resistances, since the disproportionately greater resultant effect of the thermionic device due to a given increment of change makes suchcompensation unnecessary.- It will furthermore be `understood that the strength of the winding 25 with respect to the windtig 26 may be proportioned as desired, an that the winding 25 may be omitted if desired. The weaker that the winding 25 is made with respect to the winding 26 (in either Figure 1 or Figure 2) the more rapidly and powerfully is the one solenoid made to preponderate over the other. I prefer, however, to include such a winding as the winding 25 for coaction with the thermionic-controlled winding 26 since, in such case, the winding 26 can be supplied. with less energyand the thermionic device 30 as well as the transformer 36-37 may be of less capacity. p

It will be understood, however, that if desirable, the resistance 28, hereinabove described in connection with the adjustment or setting of the apparatus, may be constructed or designed to have a temperature compensating action, and that this maybe desirable Idepending upon various practical conditions that may be met with.

I wish also to point out that it may, under certain conditions, be desirable to associate with the movable parts of the regulator an appropriate damping4 device, such as a dash pot, for example, in order to stead the action of the regulator, should suc steadying action be made necessary by the practical conditions of use. And I would also point out that by the rapidity or quicknessof action described above in connection with the operation Vof the regulating apparatus, I mean to include not necessarily a high speed -of movement of the movable parts but rather such a rapidity of action as brings about a relatively prompt restoration of the predetermined standards of electrical conditions which it is desired to maintain' in the circuit. For example, hysteresis effects, or changes or variability of friction factors in the movable parts Iof the regulator and like factors oftentimes are the cause of having the regulator maintain a relatively higher or relatively lower standard of regulation with respect to the desired or intenv ed standard, because of the fact that various factors, some of which have been illustratively mentioned above, are of such a nature ,that it takes the controlling coil or coils relatively long periods of time to overcome these factors and to bring about conditions, either electrical, mechanical or magnetic, necessary to completely restore and maintain thedesired or intended standard of re ation. The characteristics of the thermionic device and the coaction of the .latter' with the regulator, however, insure the prompt overcoming of suchfactors as have been above-mentioned illustratively and thus a high' degree of closeness and accuracy of regulation are ensured.

In both Figures 1 and 2, I have shown preferred embodiments of an arrangement for insuring against the failure of the thermionic device; I prefer to associate with the thermionic device 30 as many additional thermionic devices as may be desired, and in the drawing I have shown a single additional' thermionic device 48, though it is to be specifcally understood that additional ones may be associated with. respect to the device 30 in substantially the s'alne manner4 as is the device 48 associated with the device 30 and its respective circuits.

Referring, for example, to Figure 2, thethermionic device 48 is provided with a plate III - device and to one terminal of the Aanode 49 connected by vconductor 50 tothe winding 36 of the transformer achieved.' It willbe seen that the apparatus 1s of simple and thoroughly practical construction, is capable of inexpensive manufac- 36 lse?cpnd'ia2y ture, and is vcharacterized by highl sensitive and powerful but eicient action w enin use:

filament cathode l-51 of the supplementary-Moreover, it will be seen that the a paratus thermionic device 48 is connected substantialin parallel with the filament cathode 29 of l the device 30, but through a ela -switch enerally indicated at' 52. This re ay-switc 52 may be of ,anyv sultable construction and .is illustratively shown as being ofthe solenoid typ. It is provided with a windin 53 con- Y nected by conductors 54 and 32 to t e main line conductors 1-3 and 14 respectively, and on the generator side ofthe main switch. The relay 52 is also provided with a winding 54 which will be seen to be in circuit with the filament cathode 51 and will thus be seen to be energized only when the relay 52 has its switch -contacts closed. The winding 53 and its associated movable parts of the relay are s'o designed that, at the maintenance of the normal electrical conditions in the circuit, illustratively shown herein as the maintenance of va. predetermined voltage, the

, 29 burnin out, for example, then the elec=--- winding 53 is insuilciently' energized to cause the closure of the switchcontacts ofthe-relay 52. Thethermionic device 48-is thus main-'I tained ineffective as long as the thermionic device 30 and itsassoclated parts are' op-l erat-ive to maintain; the desired electrical conditions in the circuit. Assuming, however, that the thermionic 'device 30"becomes inoperative, as by-way of the tilamentcathode trical con itions in the circuit become abing 26 in circuit vice 30.

rary'abnormality in the electrical conditions A normal and illustratively the voltage of thesystem will begin to rise, due to the'failure of an adequate current llow through the .windwith -the thermionic de- Upon a predeterminedrise in the voltage, the coil 53 becomes suliicientl energized to close theswitch contacts of the relay 52 so that thela'ment 51 of the thermionic device 48 becr'lrliesV heated, the resultant current flow thereto "and through. the coil 54 acting by wayrofv the latter to assist the coil 53'in holding the relay contacts closed. The thermionic .device 48 is thus substituted for the inelective or inoperativedevice 30, and the tempoandssystem may be readily adjuste to meet varyigscgnditions of practical use.

As manypossible embodiments may be made of the above invention, and as many changes might be made inthe embodiment above set forth, it-isto be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a-limiting sense.

I claim as my invention: W

1. In a system of the character described, in combination a generator and a carbon pile regulator f said generator, and means for controlling said carbon pile regulator, said means includin' twosolenoids acting in opposition to ea'c other and connected to be responsive to substantially the samev changes in a function of the output of the generator, and a` thermionic or controlling the output ofdevice adapted .to cause one of said solenoids to be responsive in greater degree than the .other-ofsad solenoids.

2. In asy'stemof the character described, in combinatioma generator and a carbon ile regulator therefor; a thermionic device; means for controlling said regulator, said means including'v a'V solenoid connected to be responsive to a change in a function of the `out' ut of said generator and a second solenoiV ,@-acting in opposition to the first-men- .tioned solenoid, said first-mentioned solenoid being connected in `acircuit'in.whichis included the plateanode of a thermionic device, the filament cathode of which is connected to los be responsive to changes in a Ifunction of the output of said generator.

' 3. In apparatus of the character described, in combination, a generator, regulating means therefor adapted to control a function of the out ut thereof, said means including a thermionic device a second thermionic device; a-nd means adapted upon said function of the out utof said generator lreaching a predetermined value to make elective said second thermionic device. 4

4. In apparatus of Vthe character described, in combination, a generator, regulating means therefor adapted to control a function of the output thereof, saidmeans including a ther'- mionic device.; a second thermionic device; each of said devices having electrically heated thermionic-emission means; and means responsive to failure of flow of heating'current to the means of one device for initiating Gow of heating current to the means of the other device.

5. In apparatus of the characterdescribed, in combination, a generator, regulating means l means therefor, a plurality of thermionic dea-nd said cathodes, and means responsive to vices, oneof which is normally adapted to affect said regulating means, each of said devices having an anode and an electrically heated cathode, means connecting in parallel the space-current paths between said anOdes ineffective condition of the cathode of said one thermionic device for making effective the cathode of another of said plurality of thermionic devices.

.7. In apparatus of the character described, in combination, a generator, regulating means therefor, a thermionic device for controlling said reOulating means and having a filament electrode, a second thermionic device, connections for supplying heating current to said filament electrode from said generator, and means operated when the heating current to said filament electrode fails for bringing into action said second-mentioned thermionic device to control said regulating means.

8. In apparatus ofthe character described, in combination, a enerator, regulating means therefor, a plura it of thermionic devices each having an ano e and a filamentcathode, theanodes of said devices being connected together and in a circuit adapted to affect said regulating means and the filamcnt of one of said devices being connected to receive heating current from 'said generator, and means adapted upon failure of the filament of said one device to become heated to connect the filament of another of said' devices to receive heating current from said generator.

9. In apparatus of the character described, in combination, a generator, regulating means therefor, a coil for affecting said regulating means, and a thermionic device responsive to changes in a function of the output of said generator for controlling the energization of said coil; a second thermionic device normally ineffective, and means for making said second thermionic device effective to control the energization of said coil and operative upon failure of said first thermioic device.

10. In apparatus of the character described, in combination, a generator, regulating means therefor, a coil for affecting said regulating means, and a thermionic device responsive to changes ina function of the output of said generator for controlling the energization of said coil; a second thermionic device normally ineffective, and means including acoil responsive to an abnormal value of said function of the output of said generator for makin said second thermionic device 'effective to a c ct the energization of said coil. l

11. In apparatus of the character described, in combination, a generator, a thermionic device connected to be responsive to a function of the output of said generator for controlling the output of said generator; a second thermionic device, normally ineffective; a switch for connecting said second thermionic device to become effective for controlling the output of said generator; a coil for operating ys aid switch and responsive to an abnormal value of the said function of the output of said generator; and a second coil for holding said switch in operated position upon the restoration to normal value of the said function of the 'output of said generator.

12. In apparatus bf the character de-A scribed, in combination, a generator, regulating means therefor, a thermionic device connected to be responsive to a function of the output of said generator for controlling said regulating means and having 'a filament cathode connected to receive heating current; a second device normally ineffective; a switch for connecting said second device to become effective for affecting said regulating means;

and a coil responsive to failure of the heating current through said filament cathode for operating said switch.

13. In apparatus of the character described, in combination, a generator, a ther-- mionic device connected to be responsive to a function of the output of said generator for controlling the output thereof and having a filament cathode connected to receive a heating current; a second device normally ineffective and having a filament cathode adapted to receive heating current; a switch for connecting said second device to become effective to affect the output of said generator; a coil responsive to failure of the heating current through the filament cathode of said first device for operating said switch; and a coil responsive to the flow of heating current to the filament cathode of said second device for holding said switch closed.

14. In apparatus of the character described, inl combination, a carbon pile reguhlator, means for controlling the pressure thereon including a solenoid tending to compress said pile and a solenoid tending to relieve compression of said pile, said solenoids being connected to be responsive to the same electrical conditions, and thermionic means for causingone of said solenoids `to `have a greater effect than the other.

15. In apparatus of the character described, in combination, a carbon pile regulator, means for controlling the pressure thereon including a coil, a. thermionic device for alecting said coil and adapted to be connected to be responsive to changes in electrical conditions, a second thermionic device, and means res onsive to ineffective condltlon of said first evice for making said second device operative to affect said coil. e

16. In apparatus of -the character described, in combination, a carbon pile regulator, a lever for affecting-the pressure thereon and mechanically substantially balanced,

a pair of electromagnetic means having op- 'be connected to be responsive to the same changes in electrical conditions, each of said means having substantially the same electrical and magnetic characteristics, and ther-` mionic meansfor causingone of said electromagnetic means to have a greater responsiveness than the other.

18. In apparatus of the character `described, in combination, a compressible carbon pile regulator, means for controllingI the pressure thereon including a pair of solenoids l having opposing effects thereon and adapted to be connected to-be responsive to substantially the same changes in electrical conditions, each of said solenoids being constructed to have a substantially constant pull throughout the range of movement of the movable parts thereof for normal energization, and means for causing one ofsaid solenoids to have a greater effect than the other for a given change in the said electrical conditions.

19. In apparatus of the character described, in combination, a carbon pile regulator, means for controlling pressure thereon including a coil, a device having spaced electrodes with an electronic conduction path therebetween for aecting said coil and adapted to be connected tobe responsive to changes in electrical conditions, a second device having spaced electrodes with an electronic conduction path therebetween, and means responsive to ineifectivecondition of said. first-mentioned device for making said second mentioned device operative to affect lsaid coil.

20. In apparatus of the character described, in combination, a source of current, a work circuit supplied therefrom, regulating means for controlling a function of the energy sup lied b said source to said work circuit, sai regu ating means including a device having spaced electrodes between which electronic conduction is adapted to takev place, a second device having spaced electrodes between which electronic conduction is adapted to )take place, and means effective upon the substantial failure of one of said dev'ices for making effective the other of said devices.

21. In apparatus of the character flescribed, in combination, a compressible carbon piley regulator, means for controlling the pressure thereon including a pair of solenoids having opposing eii'ects Vthereon and adapted to,be connected to be responsive to substantially the same changes in electrical conditions, each of said solenoids being constructed to have a substantially constant pull throughout the range of movement of the movable parts thereof for normal energization, and'me'ans havinga pair of spaced electrodes between which ionic conduction takes place nfor causing one of said solenoids to have a greater eiiect than the other for a given change in the said electrical conditions.

22. In apparatus of Hthe character described, in combination, a source of current, a work circuit to be supplied therefrom, regulating means for controlling a function of the energy supplied by said source to said work circuit, said regulating means including a thermionic device connected to be responsive to said function and having a filament cathode connected to receive a heat current, a second thermionic device normally ineffective and having a filament cathode adapted to receive heating current, a switch for connecting said second device to coact with said regulating means, a coil responsive to failure of the heating current through the filament cathod ofsaid first device for operating said switch, and a coil res onsive to the flow of heatingcurrent to the lament cathode of said second device for holding said switch closed.

23. In apparatus ofthe character described, in combination, a carbon pile regulator, means for controlling pressure thereon including a coil, a device having spaced electrodes with an electronic conduction path therebetween for aifecting said coil and adapted to be connected tobe responsive to changes in electrical conditions, a second device having spaced electrodes with an electronic conduction path therebetween, a switch for making said second-mentioned device operative to affect said coil, means responsive to ineffective condition of said firstmentioned device for causing actuation of saidy switch, and means responsive to' effective condition of said second-mentioned. device for holding said `switch in actuated position.

24. In apparatus of the character described, in combinatiolna source of current,

ing device to become connected to affect said a Work circuit supplied therefrom, regulating means for controlling a function of the energy supplied by said source to said work circuit, said regulating means including a device having spaced electrodes between which electronic conduction is adapted to take place, a second device having spaced electrodes between which electronic conduction is adapted to take'plac'e, circuitcontroiling means adaptedto causesaid secv ond device to take part in the'regulation of said function of the energy `from said source, and means responsive to. a predetermined value of said function of the energy of said source for causing actuation of said circuitcontrolling means.

25. In apparatus of the character described, in combination, a source of current, a work circuit supplied therefrom, regulating means for controlling a function of the energy supplied by said source to said work circuit, said regulating means including a device having spaced electrodes between which ,electronic conduction is adapted to ,take place, a second device having spaced electrodes between which electronic conduction is adapted to take place, circuit-controlling means adapted to cause said second device to take part in the regulation of said function of the energy from said source, means responsive to a predetermined value of said function of the energy of said source for causing actuation of said circuit-controlling means, and means responsive to eiective condition of said second device for holding said circuit-controlling means in actuated position.

26. In apparatus ofthe character described, in combination, a source of current, a work circuit supplied therefrom, regulating means for controlling a function' of the energy supplied by said source to said work circuit, said regulating means including a plurality of devices, each' having spaced electrodes between which electronic conduct-ion is adapted to take place and each adapted to affect said regulating means, switching means interposed between successive devices and adapted upon actuation to cause a succeedregulating means, and means responsive to predetermined rise in the function of the energy supplied by said source to said work circuit for actuating said switching means.

27. In apparatus of the character described. in combination, a source of current,- a work circuit supplied therefrom, a carbon pile regulator for controlling a function of the energy supplied by said source to said work circuit, and means for controlling said carbon pile regulator, said means including two coils having opposed effects thereon and connected to be responsive to substantially the same changes in the function of the energy supplied by said source to said work circuit, and means having spaced electrodes between which conduction takes place for causing one of said coils to .have a greater responsiveness than the other.

28. In apparatus of the character described, in combination, a source of current, a circuit for receiving current therefrom, a carbon pile for controlling a function of the current supplied to said work circuit, two voltage responsive electromagnetic means, eachresponsive to the voltage across said circuit, the one acting 1n a direction to compress said carbon pile and the other 'acting in a direction to.

relieve compression of said carbon pile, and

means having spaced electrodes between which electronic conduction may take place for causing one of, said electromagnetic means to have a'greater responsiveness than the other.

In testimonywhereof, I have signed my name to this specification this 6th day of vMay, 1926 ALN VARLEY LIVINGSTON. 

